feat(disk, diskutil): Add new metric type disk and diskutil

[geigerj0]

Feature

This PR introduces two new metric types:

• disk: scaling based on how many megabytes of the app disk is being used
• diskutil: scaling based on how much percent of the app disk is being used

Example for disk

{
  "instance_min_count": 1,
  "instance_max_count": 3,
  "scaling_rules": [
    {
      "metric_type": "disk",
      "breach_duration_secs": 60,
      "threshold": 750, // ⬅️ scale up when app uses more than 750MB disk
      "operator": ">",
      "cool_down_secs": 60,
      "adjustment": "+1"
    },
    {
      "metric_type": "disk",
      "breach_duration_secs": 60,
      "threshold": 350, // ⬅️ scale down when app uses less than 350MB disk
      "operator": "<",
      "cool_down_secs": 60,
      "adjustment": "-1"
    }
  ]
}

Example for diskutil

{
  "instance_min_count": 1,
  "instance_max_count": 3,
  "scaling_rules": [
    {
      "metric_type": "diskutil",
      "breach_duration_secs": 60,
      "threshold": 75, // ⬅️ scale up when app uses more than 80% of its available disk
      "operator": ">",
      "cool_down_secs": 60,
      "adjustment": "+1"
    },
    {
      "metric_type": "diskutil",
      "breach_duration_secs": 60,
      "threshold": 35, // ⬅️ scale down when app uses less than 30% of its available disk
      "operator": "<",
      "cool_down_secs": 60,
      "adjustment": "-1"
    }
  ]
}

[asalan316]

LGTM

[sonarcloud]

Quality Gate passed

Issues
4 New issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarCloud